DaimlerChrysler Jeep Grand Cherokee 2002, Service Manual

Page: 238 / 284

Symptom:
*CHECKING THE VISCOUS/CABIN HEATER RELAY
POSSIBLE CAUSES
FUSED B+ CIRCUIT OPEN
VISCOUS HEATER RELAY OUTPUT CIRCUIT SHORTED TO VOLTAGE
VISCOUS HEATER RELAY OUTPUT CIRCUIT SHORTED TO GROUND
VISCOUS HEATER RELAY OUTPUT CIRCUIT OPEN
VISCOUS HEATER RELAY
TEST ACTION APPLICABILITY
1 Turn the ignition on.
With the DRB, actuate the Viscous Heater Relay.
Is the clicking during the actuator test? All
Yes
→
Test Complete.
No
→
Go To 2
2 NOTE: If the Viscous Heater Relay fuse or fuselink is open, refer to the
system schematics for all circuits that are powered by the Cabin Heater
Relay fuse or fuselink to determine the cause of the blown fuse/fuselink.
Remove the Viscous Heater Relay.
Using a 12-volt test light connected to ground, probe the Fused B+ circuit in the
Viscous Heater Relay connector.
Does the test light illuminate brightly? All
Yes
→
Go To 3
No
→
Repair the Fused B+ (Fuse/Fuselink) circuit for an open.
Perform ROAD TEST VERIFICATION - VER-2.
3 Turn the ignition off.
Disconnect the Viscous Heater harness connector.
Remove the Viscous Heater Relay.
Turn the ignition on.
Measure the voltage on the Viscous Heater Relay Output circuit.
Is the voltage above 1.0 volt? All
Yes
→
Repair the Viscous Heater Relay Output circuit for a short to
voltage.
Perform ROAD TEST VERIFICATION - VER-2.
No
→
Go To 4
4 Turn the ignition off.
Disconnect the Viscous Heater harness connector.
Remove the Viscous Heater Relay.
Measure the resistance between ground and the Viscous Heater Relay Output circuit.
Is the resistance above 1000 ohms? All
Yes
→
Go To 5
No
→
Repair the Viscous Heater Relay Output circuit for a short to
ground. Inspect the fuse or fuselink and replace as necessary.
Perform ROAD TEST VERIFICATION - VER-2.
230
DRIVEABILITY - DIESEL
ProCarManuals.com